1. Field of the Invention
The present invention relates to a catalyzer-containing muffler wherein a catalyzer is provided inside the casing of the muffler.
2. Prior Art
In recent years, as environmental problems have been drawing more public-attention, more stringent regulations for exhausted gases and noise from internal combustion engines have been enacted. In order to comply with these regulations, mufflers and exhaust-gas cleaners have become indispensable for internal combustion engines.
Generally, in the use of an internal combustion engine, provision of both a muffler and an exhaust-gas cleaner, such as a denitration or desulfuration device is indispensable. The muffler for an internal combustion engine usually includes a two-stage muffling structure in order to sufficiently reduce noises. The provision of these muffler and the exhaust-gas cleaner, however, conventionally requires a substantial space for their installation. Although efforts have been made to reduce the size of these devices, such an effort has limitations, since the muffler and the exhaust-gas cleaner respectively require a certain volume to accomplish their effect, i.e. noise reduction space for the muffler and exhaust gas treating space for the denitration device. Another problem is that since the two devices have to be prepared and installed separately, the use of these devices are costly. Particularly, in a low-power engine, the cost of the two devices comprises a substantial portion of the total cost, which is a substantial obstacle to the provision of these devices in the low-power engines.